Solvent extraction is a process used in the petrochemical industry to separate mixtures of different molecular species by contacting the mixture with a solvent that selectively removes certain of the molecular species present in the mixture. An example of a commercial solvent extraction process involves the selective dissolution of aromatic hydrocarbons from paraffinic hydrocarbons using polar solvents such as N-methyl pyrrolidone (NMP), furfural, phenol and the like. Typically, the dissolved aromatic hydrocarbons are recovered from the solvent by rectification, stripping or a combination of these means to recover a solvent containing from about 0.5 to about 5 LV % water. The solvent then is recirculated to contact fresh feed. Over time contaminants from the feed and solvent degradation products accumulate in the solvent phase. These species are acidic and may include carboxylic acids, halogens and other products which are capable of causing severe corrosion in various sections of the plant equipment with which it comes in contact.
Therefore, there is a need for a method of treating recovered extraction solvents to remove contaminants present in them.